classification of pteridophyte according to giffor and foster 1989
Answers
The term Pteridophyta was first coined by Haeckel. Eichler (1883) divided the plant kingdom into Cryptogamia and Phanerogamia. The Cryptogamia was further divided into Thallophyta. Bryophyta and Pteridophyta. Engler (1909) included the Bryophyta and Pteridophyta under Embryophyta.
Due to discovery of the fossil plants, the classification of Pteridophytes has undergone vast changes in the recent past. Older taxonomists divided the vascular plants in two divisions—Pteridophyta (primitive vascular plants with absence of seeds) and spermatophyta (presence of seeds).
However, this distinction became invalid due to the discovery of seed bearing fossil plants (Cycadofilicales). Sinnott (1935), therefore, introduced a new term Tracheophyta for a division which possess sporophyte with a well-developed vascular tissue.
Arthur J. Eames (1936) classified Tracheophyta into following four groups on the basis of nature and relation of leaf and stem vascular anatomy and position of sporangia:
Tippo (1942) called the ‘groups’ of Eames as sub-phylum. Wardlaw (1955) gave them the rank of sub-division.
According to recommendations of I.C.B.N. (1952), the name of the division should end in the suffix-phyta, of a sub-division in-phytina and a class in -opsida.
On this basis Wardlaw (1955) divided the Pteridophytes into four divisions:
(1) Psilopsida:
Sub-division Psilopsida (according to Wardlaw, 1955) or Division Psilophyta (according to Smith. 1955) includes living (Order Psilotales e.g., Psilotum), as well as fossil plants (Order Psilophytales e.g., Rhynia).
(ii) The members are sporophytic.
(iii) Roots are absent.
(iv) The organization of the plant body of the members is very simple. It is differentiated into a subterranean (underground) rhizome and an erect aerial portion.
(v) Rhizome bears tufts of unicellular Rhizoids.
(2) Lycopsida:
(i) It includes both fossil (e.g., Lepidodendron) and living Pteridophytes (five living genera e.g., lycopodium, Phylloglossum, Isoetes, Stylites and Selaginella).
(ii) Its history indicates that these Pteridophytes developed during the Devonian period of the Palaeozoic era.
(iii) The plant body is sporophytic and can be differentiated into root, stem and leaves.
(iv) The leaves are small (microphyllous), simple with a single mid vein.
(v) They are usually spirally arranged, sometimes in opposite fashion and or even in whorls.
(3) Sphenopsida:
(i) It includes both fossil plants (e.g., Calamophyton, Sphenophyllum) as well as living plants (e.g., Equisetum). It is represented by one living genus Equisetum and 18 fossil forms.
(ii) These Pteridophytes evolved during the Carboniferous period of the Palaeozoic era.
(iii) The plant body is sporophytic and can be differentiated into root, stem and leaves.
(iv) The stem in majority of the forms is long, jointed or articulated and is ribbed i.e., having ridges and grooves.
(v) Stem is divisible into nodes and internodes and is developed as upright aerial branches from the underground creeping rhizome.
(4) Pteropsida:
(i) This sub-division includes the plants which are commonly known as ‘ferns’. It is represented by about 300 genera and more than 10000 species.
(ii) These Pteridophytes were originated during the Devonian period.
(iii) They occur in all types of habitats. Majority of the ferns are terrestrial and prefer to grow in moist and shady places. Some are aquatic (e.g., Azolla, Salvinia, Marsilea), xerophytic (e.g., Adiantum emarginatum), epiphytic (e.g., Asplenium nidus), halophytic (e.g., Acrostichum aureum) or climbing (e.g., Stenochlaena).
(iv) Some members are very small while some members are tall tree like (e.g., Angiopteris).
(v) Majority of the members (except some tree ferns e.g., Angiopteris) have short and stout rhizome. The rhizome may be creeping, upright or growing above the soil.
hope it helps you
mark as brainliest